In fact, here's the lineup for the Equestrian Party:
She's a Princess. She knows magic. She loves to read. She's OCD about rules and procedure. We're guaranteed to have the smartest, most ethical President in history.
Vice President: Pinkie Pie
The Vice Presidency is pretty much a joke these days, and VPs mainly go to funerals, parties, and other functions that the President can't or wont attend. If it's a joke and it's a party, that means Pinkie Pie!
Secretary of State: Rarity
Daaahling, please! She's smooth, she's cultured, she speaks with a Mid-Atlantic accent so that she sounds European enough to win people over, but she can also be tough as nails when necessary. Isn't it time that America look good on the foreign stage again?
Secretary of the Treasury: Applejack
She's honest. If that alone doesn't qualify her to manage our nation's money, there's also the fact that she's a hard worker and knows the value of a buck (pun gleefully intended). (Her brother Big McIntosh would make an excellent Secretary of Labor, and her grandmother Granny Smith for Secretary of the Interior.)
Secretary of Defense: Rainbow Dash
Aggressive, but a team player. Has the heart of a warrior but knows enough to listen to the wisdom of others. Plus, she can perform a totally sweet Sonic Rainboom.
Secretary of the Interior: Fluttershy
Fluttershy is a friend to all animals, so naturally she will want to take care of them. But she's also kind enough to realize that humans have to be treated fairly as well. Plus, she can star down a freaking dragon, meaning she's tough on pollution.
Secretary of Health and Human Services: Zecora the Zebra
If you want to keep your people well,
You'll hearken to Zecora's spell.
Her potions will help cure what ails ya,
Even the bird flu from Southeast Asia.
Secretary of the Department of Homeland Security: Special Agent Sweetie Drops
She's a skilled agent from an elite, secret agency dedicated to hunting and imprisoning monsters. Fighting terrorists and keeping America safe ought to be a snap for her.
and finally, White House Press Secretary:
Because it's not like he could do the job any worse than the last few people who had the job.